Vergeer, who won four Paralympic tennis singles gold medals and three golds in doubles, held a news conference alongside the ATP Rotterdam Open on Tuesday, telling journalists: "It can't get any more beautiful than this."

"I've had such a crazy career. I can't get anything else to add to this. The circle is complete," the Dutch national news agency ANP quoted her as saying.

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Vergeer won her first gold medal in Sydney in 2000. She has been ranked No.1 in the world since 1999 and has not lost a singles match since January 2003.

She has always insisted that she was not chasing the record of squash great Jahangir Khan, who tallied 555 consecutive wins between 1981 and 1986.

"This is an amazing life still so why quit while I'm still winning?" she said last year. "But it's not like I'm aiming for the 500 unbeaten record, 600 or whatever."

Dutch soccer legend Johan Cruyff, who has worked with Vergeer through his charitable foundation helping children with disabilities get into sport, was also in Rotterdam and paid tribute to the player.

"She's an example for everyone. We're quick to complain of a headache or a little pain. But people like Esther go so much further to attain something," ANP quoted Cruyff as saying.

"She has such enormous drive and gives everything to win. You can only take your hat off to that."

The president of the International Tennis Federation, Ricci Bitti, described Vergeer as a "tremendous ambassador not only for tennis but also for disability sports".

"She is an inspiration to many. Wheelchair tennis owes her a huge debt of gratitude for her professionalism and her quality as a player," he was quoted as saying on the International Paralympic Committee website paralympic.org.

Vergeer was just a "little girl" when she started out in wheelchair tennis after losing the use of her legs aged eight following surgery, and she has grown up alongside the sport as it blossomed and gradually became more professional.

"It's so amazing that I can spread the message to the world basically that if you have a disability there's so much that you can still do, and a lot of people in the world still don't know that," she said in Melbourne in January last year.

Vergeer's retirement comes after British wheelchair ace Peter Norfolk, dubbed "The Quadfather", announced last month that he was giving up full-time competition and would most likely not be at the next Paralympics in Rio de Janeiro in 2016.

Norfolk, who won gold at the 2004 and 2008 Games in Athens and Beijing in the quads tournament for players with impairments to three or more limbs, carried Britain's flag at the London 2012 Games.